Reversible Molecule\nInteractions Enable Ultrastretchable\nand Recyclable Ionogels for Wearable Piezoionic Sensors

Ionogel-based piezoionic sensors feel motions and strains\nlike\nhuman skin relying on reversible ion migrations under external mechanical\nstimulus and are of great importance to artificial intelligence. However,\nconventional ion-conductive polymers behave with degraded electrical\nand mechanical properties after thousands of strain cycles, and the\ndiscarded materials and devices become electronic wastes as well.\nHere, we develop ultrastretchable ionogels with superior electrical\nproperties via the mediation of metal–organic frameworks, whose\nproperties are attributed to reversible molecule interactions inside\nthe material system. Ionogels present excellent mechanical properties\nwith breaking elongation as high as 850%, exceeding most previously\nreported similar materials, and the high conductivity enables further\napplication in sensor devices. In addition, our ionogels display superior\nrecyclability because of the reversible physical and chemical interactions\ninside material molecules, which are eco-friendly to the environment.\nAs a result, the ionogel-based piezoionic sensors deliver high sensitivity,\nflexibility, cyclic stability, and signal reliability, which are of\ngreat significance to wearable applications in human-motion detections\nsuch as throat vibration, facial expression, joint mobility, and finger\nmovement. Our study paves the way for ultrastretchable and eco-friendly\nionogel design for flexible electrochemical devices.